2 Bit Binary Encoder with Sync

This
encoder is designed to be read by three sensors and counts those encoders in a
binary pattern. Like the Quadrature Encoder this can be used to figure out if
the encoder is turning clockwise or counter-clockwise.

The sync pulses in the inner ring give you a
signal to use that identifies when the best time to "sample" the
encoder sensors. Thus you would put a sensor on that ring and when its output
indicated "black" you then read the other two encoders to return a
binary number between 0 and 2.

The image above is being shrunk by your browser
to be 100 pixels across, its native resolution is 600 pixels so if you print
it on a 600 DPI laser printer it will be a 1" encoder and at 300 DPI a
2" encoder.